考虑矩阵集A = { A = [ 0 ( n − 1 ) × 1 1 ( n − 1 ) × ( n − 1 ) − a 0 − a n − 1 ] | a _ j ≤ a _ j ≤ a ¯ j , j = 1 , 2 , 3 , 4 , . . . , n − 1 {\displaystyle {\begin{aligned}A={\begin{bmatrix}0_{(n-1)\times 1}&1_{(n-1)\times (n-1)}\\-a_{0}&-a_{n-1}\\\end{bmatrix}}\qquad |\qquad {\underline {a}}_{j}\leq {\underline {a}}_{j}\leq {\overline {a}}_{j},\qquad j=1,2,3,4,...,n-1\end{aligned}}} }
集合A中的每个矩阵都是Hurwitz当且仅当存在 P i ∈ S n {\displaystyle P_{i}\in {\text{S}}^{n}} , i = 1, 2, 3, 4,其中Pi > 0,i = 1, 2, 3, 4,使得
其中
A i = [ [ 0 ( n − 1 ) × 1 1 ( n − 1 ) × ( n − 1 ) ] a i ] , i = 1 , 2 , 3 , 4 , {\displaystyle {\begin{aligned}\qquad A_{i}={\begin{bmatrix}[0_{(n-1)\times 1}&1_{(n-1)\times (n-1)}]\\\qquad a_{i}\\\end{bmatrix}}\end{aligned}},\qquad i=1,2,3,4,}
a 1 = − [ a _ 0 a _ 1 a ¯ 2 a ¯ 2 . . . a _ n − 4 a _ n − 3 a ¯ n − 2 a ¯ n − 1 ] , {\displaystyle {\begin{aligned}\qquad a_{1}=-{\begin{bmatrix}{\underline {a}}_{0}&{\underline {a}}_{1}&{\overline {a}}_{2}&{\overline {a}}_{2}&...&{\underline {a}}_{n-4}&{\underline {a}}_{n-3}&{\overline {a}}_{n-2}&{\overline {a}}_{n-1}\end{bmatrix}},\end{aligned}}}
a 2 = − [ a _ 0 a ¯ 1 a ¯ 2 a _ 2 . . . a _ n − 4 a ¯ n − 3 a ¯ n − 2 a _ n − 1 ] , {\displaystyle {\begin{aligned}\qquad a_{2}=-{\begin{bmatrix}{\underline {a}}_{0}&{\overline {a}}_{1}&{\overline {a}}_{2}&{\underline {a}}_{2}&...&{\underline {a}}_{n-4}&{\overline {a}}_{n-3}&{\overline {a}}_{n-2}&{\underline {a}}_{n-1}\end{bmatrix}},\end{aligned}}}
a 3 = − [ a ¯ 0 a _ 1 a _ 2 a ¯ 2 . . . a ¯ n − 4 a _ n − 3 a _ n − 2 a ¯ n − 1 ] , {\displaystyle {\begin{aligned}\qquad a_{3}=-{\begin{bmatrix}{\overline {a}}_{0}&{\underline {a}}_{1}&{\underline {a}}_{2}&{\overline {a}}_{2}&...&{\overline {a}}_{n-4}&{\underline {a}}_{n-3}&{\underline {a}}_{n-2}&{\overline {a}}_{n-1}\end{bmatrix}},\end{aligned}}}
a 4 = − [ a ¯ 0 a ¯ 1 a _ 2 a _ 2 . . . a ¯ n − 4 a ¯ n − 3 a _ n − 2 a _ n − 1 ] , {\displaystyle {\begin{aligned}\qquad a_{4}=-{\begin{bmatrix}{\overline {a}}_{0}&{\overline {a}}_{1}&{\underline {a}}_{2}&{\underline {a}}_{2}&...&{\overline {a}}_{n-4}&{\overline {a}}_{n-3}&{\underline {a}}_{n-2}&{\underline {a}}_{n-1}\end{bmatrix}},\end{aligned}}}
等效地,集合 A 中的每个矩阵都是 Hurwitz 的,当且仅当存在 Q i ∈ S n {\displaystyle Q_{i}\in {\text{S}}^{n}} , i = 1, 2, 3, 4,其中 Qi > 0, i = 1, 2, 3, 4,使得